Various types of self-adhering support devices, such as utility hooks, soap dishes, towel bars, bathroom fixtures, and the like, have proven very popular with consumers for household use. These types of devices ordinarily include adhesive material preapplied to a rearwardly facing surface of the device, thus facilitating convenient mounting on surfaces such as walls or doors. One particularly successful construction is illustrated in U.S. Pat. No. 3,504,878 to Dressler.
Load-bearing support devices can be adhesively affixed to a surface in a variety of ways. One particularly effective manner includes the provision of a hydrophilic substrate coated with a moisture-activated adhesive, with the substrate bonded to the device such as by molding the device directly against the substrate. When the moisture-activated adhesive is moistened it will bond with the surface to which it is attached. When the adhesive dries, it "sets up" or cures, and firmly adheres to the surface. However, in order for the adhesive to cure and set up effectively, the adhesive must dry thoroughly. If the moisture-activated adhesive is applied to a hydrophilic or porous substrate, evaporation of water from the adhesive after the device has been applied to a surface is facilitated. In fact, without this type of porous substrate, the adhesive will probably not dry sufficiently after the device is affixed to a surface for the device to support significant loads. Fibrous inserts made of materials such as wood have been used as hydrophilic substrates that permit the evaporation of moisture from the moisture-activated adhesive coated substrate after the device is affixed to a surface.
Nevertheless, use of fibrous inserts as the adhesive backing for load-bearing substrates can be problematic. If the fibrous insert is warped or is otherwise not flat, it will not fully contact the surface on which the load-bearing support device is mounted. This reduces the strength of adhesion between the load-bearing support device and the surface to which it is attached. Although wood veneer is commonly employed as a fibrous backing member or insert for load carrying support devices, wood warpage is a common problem. Wood has a tendency to warp when exposed to changes in temperature or when moisture evaporates from the wood. Moreover, this warpage problem becomes more acute as the size of the fibrous inserts increases.
Additionally, when molten synthetic material is used to form the load-bearing support device and it cools to form the molded support device, the slight changes in configuration and dimension which accompany this cooling also tend to warp the wood backing member.
Even when an automated apparatus, such as disclosed in U.S. Pat. No. 4,466,787 to Ragir et al., is employed to substantially concurrently cut, position and bond wood backing members to support devices, warpage of the wood backing materials imposes constraints upon the efficiency of manufacture. To abate warpage, the adhesive is not applied to the wood backing prior to it being applied to the support device, because evaporation of the moisture from the adhesive warps the wood. This warpage problem is avoided by applying the adhesive onto the wood after it is bonded to or formed as a part of the support device.
Since it is more expensive, time-consuming and complex to apply the adhesive onto the wood backing member of individual support devices, rather than apply adhesive to large rolls of wood prior to cutting and bonding of the individual wood inserts, wood backing members that have a tendency to warp when dried are a significant impediment to a streamlined, efficient process for producing these types of relatively low-cost consumer articles.